Laser method for shaping of optical lenses

Abstract

A method for making accurate and precise customized corrections to the surface of an optical lens is described. An electronic correction contour is generated from a measured refractive correction for a patient, and transferred to the surface of the lens by ablation etching with one or more laser pulses. After each of the laser pulses, the refractive properties of the lens are measured and compared to the electronic contour correction derived from a patient's refractive correction. The ablation etching is terminated in localized areas where the refractive properties match the electronic correction contour. End point detection includes monitoring refractive qualities of the lens during the recontouring process, modifying the pattern through changes in the laser pulses.

Description

1. Field of the InventionThis invention relates to a laser method for rapid and accurate shaping of optical lenses.2. Description of Related ArtThe use of ablation etching to pattern polymeric material is well known in the art. In U.S. Pat. No. 4,508,749, for example, Brannon et al. discloses an ultraviolet radiation based method for etching patterns in polyimide layers located on integrated circuit substrates, and subsequently depositing an electrical circuit pattern thereover to form electrical interconnections to elements of the integrated circuit. In U.S. Pat. No. 5,236,551, Pan describes a laser-based photoablative etching process for patterning a polymeric film which is subsequently used as a mask for chemical etching of patterns in an underlying metal layer.Optical lenses produced from polymeric substances such as polycarbonate are well known in the art, and many standard molded lenses are items of commerce. Kohan, in U.S. Pat. No. 5,851,328, and Greshes in U.S. Pat. No. 6,07...

AI Technical Summary

Problems solved by technology

Although correction factors for a patient can be determined with a great deal of accuracy and precision, commercial lenses are provided with standard corrections which do not necessarily fit a given patient's individuals needs.

Custom ground lenses are prohibitively expensive for most patients, as the process of custom grinding requires a highly skilled optician, with experience in lens reshaping.

As a result, most patients must accept the standard correction lenses that are available, and consequently do not achieve optimum visual acuity.

Because the lens is rotated on a spindle in this method, however, the corrected surface is limited to a contour which is concentric with the spindle center.

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